X-59 Quiet Supersonic Transport Study Using Stallion 3D
I ran a new quiet-supersonic study at Mach 1.45 and 55,000 ft using the built-in atmosphere tables and Cartesian solver in Stallion 3D. The goal was to reproduce and understand the kind of pressure distribution seen in the NASA X-59 QueSST demonstrator, which recently completed its first flight. The idea is the same: manage the shock pattern so the ground hears a soft “thump” instead of a sonic boom.
Shock Management Along the Nose
The simulation shows a controlled series of small compressions marching down the forebody rather than one big, coalesced shock. That’s exactly what quiet-supersonic shaping is about—spreading the pressure rise (Δp/Δx) gradually so the far-field signature becomes a sequence of gentle steps instead of a single N-wave.
At these flight conditions, the distributed shock train is similar to what the X-59 team reported during their low-boom configuration tests. It’s encouraging to see Stallion 3D’s Navier–Stokes solver naturally produce the same kind of flow behavior on a simple Cartesian grid.
Canopy and Inlet Shoulder Interaction
Right behind the cockpit, a red-blue compression and expansion pattern forms where the fuselage grows into the wing root. This region is a classic challenge in supersonic design—where cross-section growth and lifting surfaces meet, shocks can thicken and contribute to secondary noise.
It’s good to see that Stallion 3D’s refinement zone resolves these local gradients clearly, without any hand-built body-fitted grid. The automatic cell concentration gives an accurate look at how geometry transitions affect both drag and acoustic signature.
Aft-Body and Tail Effects
The aft wing and tail surfaces are doing real aerodynamic work. The pressure remains mostly clean, but there are still distinct compression and expansion regions being shed downstream.
In low-boom design, the rear shaping is as important as the nose. The aft body determines how the pressure signature closes—the part that controls how the sonic waveform ends. That’s the part that often separates a “thump” from a “bang.”
Refinement Zone and Solver Performance
The local grid density around the aircraft shows that the refinement box is working exactly as intended. It captures oblique shocks and shear layers efficiently, even at Mach 1.45, without requiring a fitted mesh.
From a numerical standpoint, this confirms that Stallion 3D’s Cartesian method is practical for supersonic concept studies—especially for early X-59-style configurations or general quiet supersonic transport layouts.
Realistic Flight Condition
The run used true high-altitude conditions (55,000 ft, Mach 1.45) from the built-in atmosphere model. These are the same conditions typically quoted for quiet-supersonic cruise tests and community response research under NASA’s QueSST program.
That realism matters for both acoustics and aerodynamics. At these pressures and densities, thin, swept lifting surfaces behave differently than they do in low-altitude transonic tests.
Next Steps
- Extract the far-field pressure trace along the ground track (Δp vs. time) to evaluate perceived loudness.
- Quantify lift, drag, and moment coefficients (CL, CD, CM) to separate wave drag from viscous effects.
- Run sensitivity tests by shortening the nose or modifying canopy cross-section to see how it reshapes the shock train.
Conclusion
This quiet-supersonic run demonstrates what Stallion 3D does best—showing real aerodynamic detail from first principles without external meshing or post-processors. The solver’s ability to capture distributed shocks, canopy interactions, and aft-body effects all in one pass makes it an effective tool for early design of low-boom aircraft like the X-59 QueSST.
It’s not about pretty colors; it’s about credible data at real flight conditions. The results show a clean, believable Mach 1.45 solution with controlled shock structure—the kind of solution that points the way toward practical, certifiable overland supersonic transport.
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